Abstract: In order to protect and utilize the Acanthopanax senticosus resources reasonably, taking the typical Acanthopanax senticosus community in Xiaoxing’an Mountains of Heilongjiang Province as the research object, the relationship between the species diversity of Acanthopanax senticosus community and the altitude gradient was explored, and the influence of altitude factors on the species diversity of the community was analyzed. Results showed that:（1）With the increasing of the altitude, the species and number of arbors and shrubs in Acanthopanax senticosus community increased first and then decreased, while the species and number of herbs generally decreased. The α diversity index of arbor layer had little change along the altitudinal gradient. The α diversity index of the shrub layer initially increased and then decreased with the increase of altitude gradient. The α diversity index of herb layer showed a downward trend. There was a negative correlation between α diversity index and altitude, and a negative correlation between α diversity index and richness index at 0. 05 level. Species richness contributed the most.（2）Cody index β_c firstly decreased and then increased with the altitude, and the lowest point was in the middle altitude area（447—469 m）. Sorenson index C_s showed a trend of first increasing and then decreasing with the increase of altitude, and the highest peak value still appeared in the middle altitude area（447—469 m）.（3）The greater the difference of altitude gradient, the lower the community similarity. There were dissimilar levels among Acanthopanax senticosus communities at different altitudes. Within the study scope of Xiaoxing’ an Mountains, species in Acanthopanax senticosus communities with different altitude gradients α diversity, Cody index and Sorenson index all had certain variation rules, which indicated that altitude gradient was one of the important factors affecting the biodiversity of Acanthopanax senticosus community.